In recent years, advanced features such as a large capacity telephone number registration function and an e-mail sending and receiving function have rapidly progressed in electronic information devices such as mobile telephones from the aspect of an improvement in performance. However, along with this increase in performance, personal information including of a private nature such as names and telephone numbers of people and e-mail addresses has come to be saved in large quantities in the memory of mobile telephones. Since such large quantities of personal information being improperly used by third parties leads to problems involving privacy, a means is needed to prevent impropriety by third parties.
As a means to prevent improper use by third parties other than the possessor, conventional mobile telephones have been provided with a dial lock function. A conventional dial lock function has a function that, after detecting the opening or closing of the mobile telephone, locks the dialing based on setting information that is stored in advance, and moreover has a function that sets the time and time duration of the dial lock by using a timer or time counting function (for example, refer to Patent Document 1).
[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2004-343677